Laser scanning of objects is typically performed through air. That is, the laser light passes through only one medium between a laser generator and the target object, and through the same medium between the object and an imaging camera. The object is typically rotated in the path of the laser line while the laser line generator and imaging camera remain stationary.
Objects, including human or mammalian breasts or limbs, must often be immersed in a fluid when ultrasound, microwave, or certain other imaging technologies are performed in order to optimize coupling of ultrasound and microwaves from transducers or antennae to the object. The fluid typically has a substantially different index of refraction than that of air, and light crossing boundaries of air to container, air to fluid, or container to fluid, is subject to refraction at those boundaries. Such refraction may cause substantial distortions in laser-scanned surface maps of the object. A. Yamashita, et al, Proceedings of the 2005 IEEE International Conference on Robotics and Automation, Barcelona, Spain, April 2005, 3-D Measurement of Objects in Unknown Aquatic Environments with a Laser Range Finder, illustrates that an object imaged in a cylindrical container of fluid is subject to substantial distortion. Yamashita then describes a procedure for triangulating points of a surface of the object as located by a laser rangefinder having a single laser and camera, then using ray tracing to correct such point locations to give corrected point locations.
While not historically used for image correction while measuring objects in fluid, image morphing has been used in other fields such as film. A. Gothalsby Piecewise Linear Mapping Functions For Image Registration, Pattern Recognition. Vol. 19, No. 6. pp. 459-466. 1986, describes methods for warping an image such that reference points in that image align to reference points in another image.
Where the object is an anatomical part of a human or other large mammalian subject, it can be undesirable to rotate the object.